1. Field of the Invention
The present invention relates to automatic photoprocessing equipment for the processing of undeveloped photographic film. In particular, the invention relates to a magnetic drive apparatus for a horizontal in-line film disc processor.
2. Description of the Prior Art
The processing of photographic film includes contacting the film with a plurality of processing fluids in a selected order and for selected time periods to properly develop the images thereon. Because the film is light-sensitive, the processing must be done in the dark. Once the film has been contacted with the fluids as desired, it is also necessary to dry the film before further processing can be performed, such as making prints or slides. Numerous machines have been devised for processing film in strip or web form. However, this type of apparatus is wholly unsuited for processing film in a disc film format where the individual photographic images are located circumferentially about a central hub, as shown, for example, in U.S. Pat. No. 4,194,822, granted to Sethi on Mar. 25, 1980. PG,3 Thus, the introduction of cameras using film in a disc film format had led to the development of processing machines specifically for film discs.
Processing machines and devices developed specifically for disc film include those shown in the following U.S. Patents:
______________________________________ Patentee Pat. No. Issue Date ______________________________________ Michal 4,252,430 02/24/81 Harvey 4,188,106 02/12/80 Solomon 4,178,091 12/11/79 Hutchinson 4,167,320 09/11/79 Harvey 4,112,454 09/05/78 Hutchinson 4,112,453 09/05/78 Patton 4,112,452 09/05/78 ______________________________________
In addition to the devices shown in these patents, several disc film processing devices are shown in the following Research Disclosures:
______________________________________ Disclosure No. Title ______________________________________ 172 Research Disclosure, August 1978 17258 Horizontal In-Line Photofinishing Processor 17262 Method and Apparatus for Treating Elements of Photographic Film 17263 Improved Horizontal Film-Processing Apparatus 17264 Improved Vertical Film-Processing Apparatus 17265 Rotary Film-Processing Apparatus 174 Research Disclosure, October 1978 17429 Processor Concept ______________________________________
Disc film processing machines are also shown in two brochures of the Eastman Kodak Company of Rochester, N.Y., entitled "KODAK Disc Film Processor, Model 200" and "KODAK Disc Film Processor, Model 1000."
Since the processing of photographic film must be carried out in the dark, a film disc processing machine must either be located in a darkroom or have some means for shielding the undeveloped film discs from light during processing to prevent damage to the photographic images on the film. As shown in many of the devices disclosed above, it is efficient to process a plurality of the film discs together by mounting them on a spindle, which is then carried through the processor from start to finish as a unit. The spindle unit is conveyed from tank to tank of processing fluid in sequence, with the spindle being rotated to uniformly coat the film discs thereon with processing fluid.
As shown generally in U.S. Pat. No. 4,178,091 granted to Solomon on Dec. 11, 1979, and U.S. Pat. No. 4,112,452 granted to Patton on Sept. 5, 1978, prior art devices to rotate the spindle while the film discs thereon are immersed in processing fluid have involved complicated gearing arrangements (as in Patton) or friction drives (as in Solomon). Both of these spindle drive concepts, and other mechanical spindle rotation arrangements are unsuitable for use on a disc film processor for a number of reasons. Such arrangements have a relatively large number of moving parts (subject to wear, tear and misalignment through constant use) and, in addition, when using a gearing arrangement with a separate gear for each processing station, the spindle must be engaged and disengaged properly at each station for proper processing, which is not a simple operation. A friction drive device also has a large number of moving parts, and because of its use adjacent fluid processing stations, it is highly subject to reduced efficiency because of spill-over of fluid which tends to reduce the friction necessary for the parts to engage properly for rotation.
None of these prior art devices discloses an automatic processor for undeveloped photographic film discs which has a spindle rotation device which rotates the spindle at each processing station of the processor without mechanical coupling. The spindle rotation devices of the prior art are unsuitable for efficient and constant use on a horizontal in-line film disc processor because of their vulnerability to breakdowns and misalignment. Such efficiency problems are amplified in the photographic film processing area because of the unique nature of the workpiece being processed. The photographic images carried on the film discs are unique, one of a kind items, which cannot be reproduced if damaged or destroyed. Thus, it is necessary for each and every film disc to be properly processed, without any interruption or interference with the processing process.